Deep fried foods (hereinafter referred to as "deep frieds") are prepared by coating vegetables, meat, fish, shellfish, etc. with batter containing wheat flour, salt, baking powder, a variety of flavorings, spices, water, and so on, and deep frying in fat or oil. Typical deep frieds are fritters and tempura.
The wheat flour used as a principal ingredient of deep frieds is soft wheat flour obtained from soft wheat having a low protein content, such as Western White Wheat produced in the U.S.A.
However, when deep frieds are prepared by use of soft flour, there are noted the following disadvantages. The amount of coating is insufficient due to the low viscosity of the batter. In addition, if the deep frieds are frozen for storage purposes and then thawed in a microwave oven, the soft but crispy texture inherent to deep frieds is lost, and disagreeable gum-like texture.
Regarding the former problem, i.e., insufficient coating, a solution has been proposed by Japanese Patent Application Laid-Open (kokai) No. 62-14756, which discloses the use of oil/fat-treated starch prepared by adding edible oils or fats to waxy cornstarch or waxy rice starch, to thereby raise the viscosity above a certain level. However, this method is not effective for improving the texture of deep frieds after they are thawed in a microwave oven.
In order to improve the texture of deep frieds after they are thawed, Japanese Patent Application Laid-Open (kokai) No. 6-253763 discloses the use of a specific flour which contains protein powder, pulverized malt syrup, fatty acid esters, and rice powder or potato starch powder. However, satisfactory results have not yet obtained from this method.
Steamed Chinese manju are food similar to dumplings, and prepared by wrapping a filling such as sweat bean jam in a dough and then steaming. The dough is generally prepared by adding sugar, oils and fats, yeast, synthetic baking powder, emulsifiers, gelling agents, food colors, etc. to a flour blend primarily containing wheat flour--for example, a combination of soft wheat flour and hard wheat flour, a combination of semi-hard wheat flour and hard wheat flour, or a sole use of semi-hard wheat flour--and optionally including rice flour, starch, etc.
Recently, steamed Chinese manju which are produced in a factory are often stored and distributed under refrigerated conditions or in a frozen state. However, when steamed Chinese manju are cooled or frozen, they often become hard due to retrogradation of gelatinized starch. Therefore, Chinese manju that have been stored in a refrigerator or in a frozen state must be sufficiently heated before consumption so as to re-gelatinize the retrograded starch. Generally speaking, starch contained in Chinese manju is regelatinized by the application of steam for a suitable time (about 10 minutes), to thereby restore the Chinese manju to the precooled or prefrozen state.
These days, microwave ovens have rapidly become popular due to their convenience and high level of safety. They are now considered indispensable cooking appliances for home use. Therefore, it is desired that steamed Chinese manju that have been stored in a refrigerator or a freezer can be cooked by the application of heat in a microwave oven.
However, compared with the reheated manju cooked in a conventional steamer, the one reheated in a microwave oven have a hard and gummy texture.
This phenomenon is considered to be attributed to the unique mechanism of microwave ovens: heat is applied to Chinese manju from inside thereof and cooking is completed within a short period of time. Also, when heated Chinese manju are left to stand for a while, moisture on the surface easily evaporates.
As a measure to solve these problems, recent approaches to improve texture often include addition of starch, sugar, oils and fats, emulsifiers, gelling agents, etc.
However, even when these additives are incorporated, Chinese manju obtained by cooking in a microwave oven still have gummy and hard texture as compared to steamed Chinese manju reheated with a steamer. In addition, the former Chinese manju often provide disagreeable taste and flavor.
In the meantime, it is accepted that hardening of a Chinese manju dough upon gelatinization is partly due to retrogradation of gelatinated starch. Starch is composed of linear amylose and amylopectin, wherein glucose units are linked by .alpha.1-4 linkages, but the latter also contains some branching .alpha.1-6 bonds. Retrogradation of amylose is more remarkable than that of amylopectin. Starch that contains only very small amounts of amylose is called waxy starch. Attempts to solve tough texture due to storage in a refrigerator or a freezer or hardening of Chinese manju as a result of microwave cooking have involved the addition to Chinese manju dough of waxy rice flour, waxy rice starch, waxy corn flour, or waxy cornstarch. However, such attempts have not yet produced satisfactory results. In addition, taste and flavor are sometimes dissatisfied.
Generally speaking, gyoza and shumai are prepared by wrapping a filling (meat, vegetables, etc.) in dough sheets such as a pasta wrapping for a chinese meat dumpling (gyoza) and for a steamed meat dumpling (shumai), and then steaming. The dough sheets are prepared by adding, as required, salt, emulsifiers, vegetable oils, gelling agents, food colors, etc., to a flour blend primarily containing wheat flour which optionally includes rice flour, starch, etc.
Recently, these types of foods, i.e., dough-wrapped foods, which are produced in a factory are often stored and distributed under refrigerated conditions or in a frozen state.
However, when dough-wrapped foods are cooled in a refrigerator or a frozen, and then reheated, they often have a disagreeable tough texture. Particularly, dough-wrapped foods whose starch has once been gelatinized by the application of heat come to have significantly hard edge portions.
Therefore, in order to prevent the texture from becoming tough, and in particular to maintain soft texture of edge portions, addition of starch, sugar, oils and fats, emulsifiers, etc. has been a common practice.
However, even when these additives are incorporated, not only are their effects insufficient, but also disagreeable taste and flavor often result.
It has been accepted that hardening of a dough-wrapped foods upon gelatinization is partly due to retrogradation of gelatinized starch. Starch is composed of linear amylose and amylopectin, wherein glucose units are linked by .alpha.1-4 linkages, but the latter also contains some branching .alpha.1-6 bonds. Retrogradation of amylose is more remarkable than that of amylopectin. Starch that contains only very small amounts of amylose is called waxy starch. Attempts to solve tough texture caused by storage in a refrigerator or a freezer have involved the addition of waxy rice flour, waxy rice starch, waxy corn flour, or waxy cornstarch to the dough sheets. However, such attempts have not yet produced satisfactory results in their taste and flavor.
Okonomiyaki are foods prepared by adding salt, a variety of flavors, dashi-jiru (soup stock), egg, water, meat, seafood, vegetable, etc. to wheat flour, stirring the resultant mixture, and then baking. Takoyaki are similarly prepared with the exception that pieces of octopus are added to batter and the octopus-containing batter is baked in a special pan so as to produce a number of ball-shaped takoyaki at one time.
As the wheat flour used as principal ingredient of okonomiyaki and takoyaki, there are employed soft wheat flour obtained from soft wheat having a low protein content, such as Western White Wheat produced in the U.S.A., and semi-hard wheat flour which contains domestic Japanese wheat flour.
However, since okonomiyaki and takoyaki prepared from these types of wheat yield a batter of low viscosity, the volume of the foods after baking is not satisfactory, and resistance to the teeth is too weak, leaving the eater with an unsatisfied feeling.
Conventional attempts to solve these problems have involved the addition of polysaccharides or modified starches as viscosity-increasing agents or texture improvers. However, these approaches do not provide sufficient viscosity-increasing effects, and do not achieve, to a satisfactory level, improvement of texture of okonomiyaki and takoyaki. In addition, there is a disadvantage that texture is impeded. Japanese Patent Application Laid-Open (kokai) No. 6-303947 discloses a method for preparing takoyaki by heating batter so as to provide a proper viscosity, dividing the batter, and then baking. This method includes an intricate procedure of heating the batter and adjusting the viscosity to a proper level. Moreover, the texture and taste are not satisfactory.
These days, okonomiyaki and takoyaki are sometimes stored in a refrigerator or a freezer, and when consumed they are heated in a microwave oven. In this case, there is a problem that texture of reheated okonomiyaki and takoyaki significantly deteriorates.
Accordingly, an object of the present invention is to provide deep frieds, steamed Chinese manju, dough sheets, okonomiyaki, and takoyaki, which provide excellent texture and taste not only immediately after preparation, but also after storage in a refrigerator or a freezer and then heating and thawing in a microwave oven, etc.